In operation of hybrid and battery-powered electric vehicles, a challenge is to maintain a battery temperature which is suitable for optimum high-voltage battery performance. Battery chemistry composition may lead to reduced battery performance during operating temperature extremes and may require battery cooling and heating maintenance for optimum battery operation. During different phases of vehicle operation, the high-voltage vehicle battery may require charging and discharging which may generate heat that must be dissipated. However, in some operating environments, the battery may require active heating or cooling to maintain a specific battery temperature. Battery heating and cooling may require an input of energy from onboard or other sources, reducing fuel economy. Moreover, battery temperature extremes may severely limit battery power and energy capabilities.
Accordingly, a variable insulating battery pack system and method which controls the temperature of a battery pack for optimum performance in a hybrid or electric vehicle or other application is needed.